The N-methyl carbamate derivatives of 5-t-butyl-2,3-xylenol and 5-t-butyl-3-cresol are known to be effective insecticides for the control of a variety of insects, including the green rice leafhopper and several planthoppers. The N-methyl carbamate compounds are prepared from the corresponding respective butylated phenols by reaction with methyl isocyanate.
A simple method of preparing 5-t-butyl-2,3-xylenol or 5-t-butyl-3-cresol is not known in the literature since butylation under normal conditions occurs ortho or para with respect to the hydroxyl group and not meta. With regard to 5-t-butyl-2,3-xylenol, even the simplest known synthesis involves 3-steps starting from 0-xylene.
I have found a relatively straight-forward method of preparing 5-t-butyl-2,3-xylenol and 5-t-butyl-3-cresol. The method is also useful for preparing homologs of these materials wherein the methyl group is replaced by a C.sub.2 -C.sub.6 primary alkyl group.
The important features of my process are the use of a specific type of catalyst and a specific temperature range.